tls: replace ECDSA_C and PK_CAN_ECDSA_SOME with key exchange related ones

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/ssl_client.c b/library/ssl_client.c
index dc2b650..eab84c1 100644
--- a/library/ssl_client.c
+++ b/library/ssl_client.c
@@ -375,7 +375,7 @@
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
         (defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_OR_ECDHE_1_2_ENABLED) || \
-        defined(MBEDTLS_ECDSA_C) || \
+        defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
         defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED))
         *tls12_uses_ec |= mbedtls_ssl_ciphersuite_uses_ec(ciphersuite_info);
 #endif